Vacuum-sealing fresh-cut or chopped romaine lettuce in Mason jars will keep it fresh for up to 10 days. It's "salad in a jar" my way. It makes it easier to eat a salad every day!
Wash romaine lettuce well, leaving the leaves intact at the base.
Cut lengthwise through the entire head at least 4-5 times.
Now slice crosswise about 3/4 to 1 inch apart according to your preference.
Fill salad spinner and run under the faucet one more time. Spin dry.
Dump into a very large bowl. Fill jars with chopped, spun-dry lettuce. I pack them as tightly as possible.
Seal jars using a wide-mouth jar attachment and a vacuum-pack machine. Screw on rings as insurance to keep lid sealed.
Refrigerate up to 10 days depending on how fresh your lettuce is when you started this process.
Notes
The number of servings or quart jars you end up with depends on how many heads of romaine you use and how compact and large they are. It will also be affected by how tightly you pack the lettuce into the jars.I use hearts of romaine because the inner leaves last longer than the dark green leaves on a whole head of romaine. In general, one "heart of romaine" lettuce will fill one quart jar, but that varies.